A number of products and processes have been proposed heretofore directed at counteracting the acidity of streams and lakes which results from acid rain. All such products and processes have had various shortcomings whereby no universally acceptable solution has been found to overcome this problem.
One approach has been to spread lime, CaO or Ca(OH).sub.2, in powdered or pellet form, onto the surface of the body of water to be treated. Used in large quantities, this high pH material alters pH of the surface water very rapidly, causing detrimental effects to any living matter in the lake or stream. If used in small quantities, the treatment is short-lived, requiring frequent, time consuming applications.
Recent research involved attempts at neutralizing the acidic effect of acid rain on fresh water by slowly disintegrating portland cement concrete placed in the water to be treated.
In dealing with a somewhat remote problem, U.S. Pat. No. 2,546,586 proposes combining 55 parts plaster with 45 parts hydrated lime and 5 parts diatomaceous earth to form slightly soluble pellets to raise the pH of oil well brine from 6.4 up to 8.6 and thus prevent corrosion of the tubing in the well.
In order to produce an insoluble cementitious block for exterior building walls, U.S. Pat. No. 3,414,462 teaches combining from about 10% to about 90% lime with about 90% to 10% plaster, adding water, compressing the mix to at least 100 p.s.i., and carbonating the lime on the exposed surface.